My wife and I got a 7's setup as a step up from cig-a-likes. On the good side, they opened up the world of "better than cig-a-likes" and buying juice in 30ml bottles to us. On the bad side, because of their proprietary nature, we only used them for about a month.
My advice? Get an eGo setup and toss the 7's hardware. Use the charger that came with your eGo and don't mix and match.